#include <QtGui>

int main (int argc, char* argv[]) { /* start of function "main" which
    returns int */
    QApplication app(argc, argv); /* start of every Qt GUI application */
    QTextStream cout(stdout, QIODevice::WriteOnly);     /* create a QTextStream to standard output. */

    // Declarations of variables
    int answer = 0; /* must be defined outside the do loop, because it is
        used in the condition, outside the do block */

    do {
        // local variables to the loop:
        int factArg = 0;
        int fact(1);
        factArg = QInputDialog::getInteger(0, "Factorial Calculator",
            "Factorial of:", 1); /* Pop up dialog, wait for user to
        enter an integer, return it */
        cout << "User entered: " << factArg << endl;
        int i=2;
        while (i <= factArg) {
            fact = fact * i;
            ++i;
        }
        QString response = QString("The factorial of %1 is %2.\n%3")
            .arg(factArg).arg(fact)  /* each %n is replaced with an arg() value */
            .arg("Do you want to compute another factorial?");    /* long statements can continue
                on multiple lines, as long as they are broken on token
                boundaries. */
        answer = QMessageBox::question(0, "Play again?", response,
            QMessageBox::Yes | QMessageBox::No); /* bitwise or of 2 values */
    } while (answer == QMessageBox::Yes);
    return EXIT_SUCCESS;
}